hashes.sdbm

This algorithm was created for sdbm (a public-domain reimplementation of ndbm) database library. It was found to do well in scrambling bits, causing better distribution of the keys and fewer splits. It also happens to be a good general hashing function with good distribution. The actual function (pseudo code) is:

for i in i..len(str):

hash(i) = hash(i - 1) * 65599 + str[i];

What is included below is the faster version used in gawk. [there is even a faster, duff-device version] The magic constant 65599 was picked out of thin air while experimenting with different constants. It turns out to be a prime. This is one of the algorithms used in berkeley db (see sleepycat) and elsewhere.

source: http://www.cse.yorku.ca/~oz/hash.html

Functions

sdbm(→ int)

Function implements sdbm hash, easy to use, great for bits scrambling.

Module Contents

hashes.sdbm.sdbm(plain_text: str) → int

Function implements sdbm hash, easy to use, great for bits scrambling. iterates over each character in the given string and applies function to each of them.

>>> sdbm('Algorithms')
1462174910723540325254304520539387479031000036

>>> sdbm('scramble bits')
730247649148944819640658295400555317318720608290373040936089